A radiographic apparatus used in the medical field, industrial field or nuclear field will be described as an apparatus using the communication apparatus, X-rays will be described as an example of incident radiation, and an X-ray image pickup apparatus will be described as an example of radiographic apparatus.
An X-ray image pickup apparatus A1 is in form of a flat panel X-ray detector (FPD: Flat Panel Detector) which, as shown in FIG. 1, includes a gate drive circuit 1, a circuit 2 for detecting elements, charge-to-voltage converting amplifiers 3, an analog-to-digital converter 4, a panel control unit 5, an image correcting unit 6 and a communicating unit 7. In addition, an image buffer memory 8 is provided to store pixel values converted into digital values by the analog-to-digital converter 4, and the panel control unit 5 and image buffer memory 8 are electrically connected. Further, a parameter memory 9 is provided to store parameters used in image corrections by the image correcting unit 6, and the image correcting unit 6 and parameter memory 9 are electrically connected.
Arranged outside the X-ray image pickup apparatus A1, as shown in FIGS. 1 and 2, are an FPD power source A2 for driving the apparatus, and a control and image processing apparatus A3 as an external apparatus. As shown in FIG. 2, the control and image processing apparatus A3 has a communicating unit 11, an image processor 12 and a controller 13. The communicating unit 7 of the X-ray image pickup apparatus A1 and the communicating unit 11 of the control and image processing apparatus A3 are connected through an optical transmission device such as optical fiber F. Thus, the X-ray image pickup apparatus A1 is connected to be capable of communication to the control and image processing apparatus A3 which is an external apparatus. Optical fiber is suitable for transferring high-speed serial signals. The “serial signal” indicates a continuous transfer of each data, while the “parallel signal” described hereinafter indicates a simultaneous and parallel transfer of a plurality of data.
X-rays incident on the FPD are converted into electric charges (carriers) by an X-ray conversion layer 23 (see FIG. 3) formed of a semiconductor thick film such as of amorphous selenium, to be stored in capacitors Ca through corresponding detecting elements Du. The charges stored in the capacitors Ca are read under control of thin-film transistors Tr, converted into voltage and amplified by the charge-to-voltage converting amplifiers 3, and converted from analog voltage values into digital values by the analog-to-digital converter 4 connected downstream of the charge-to-voltage converting amplifiers 3 to be once stored as pixel values in the image buffer memory 8. Such processes are carried out on a pixel-by-pixel basis. The image correcting unit 6 reads, from the image buffer memory 8, pixel values resulting from these processes carried out for all pixels corresponding to the detecting elements Du and arranged for respective pixels (image), and performs calculations for image corrections (lag correction, offset correction and so on) based on parameters for the image corrections stored beforehand in the parameter memory 9. The results are transferred by the communicating unit 7 to the communicating unit 11 of the control and image processing apparatus A3. The series of these operations and the processes in the FPD is controlled by the panel controller 5.
In the control and image processing apparatus A3, the image processor 12 carries out image processing of the data received by the communicating unit 11. This apparatus carries out control of the entire FPD, and calculation and transmission of the parameters for image corrections used by the FPD. The calculation and transmission of the parameters for image corrections are carried out at a time of calibration (correction) which is, for example, after power-on of the FPD power source A2.